It is a world much like Earth, on the surface. The names of the countries are different, the languages different, but people are people. At least, they were. Fifteen years ago, as technology was ushering in a global shift in how the world communicated, the magic came back. Mythical beasts awakened and rose, and all across the world humanity rediscovered the wonder and mystery of the arcane.
Yet at the same time, Heaven itself came down upon mankind for dabbling in these forbidden powers, seemingly. The angels descended from on high, laying waste to entire cities at once. Stricken, humanity responded in the only way they could: by fighting back. With military might, with fumbling magics of their own, even pacting with extradimensional 'demons' to battle the conquering forces of the Almighty.
Some have started to realize that the forces of Heaven are much easier to understand than they had anticipated, though. Some have begun to suspect that the Almighty is not almighty at all, and that Heaven is not such a fantastic and mystical place as it pretends...